朱晓丽,寇志健,王军强,尚小清,陈超,耿盼瑶.生物炭固定化硫酸盐还原菌对Cd2+吸附及作用机制分析[J].环境科学学报,2021,41(7):2682-2690
生物炭固定化硫酸盐还原菌对Cd2+吸附及作用机制分析
- Adsorption of Cd2+ by sulfate reducing bacteria immobilized biochar
- 基金项目：国家重点研发计划（No.2019YFD1002404）；陕西省重点研发计划项目（No.2019NY-200，2020ZDLNY06-06，2020ZDLNY07-10）；西安市科技计划项目（No.2019-GXYD18.9，20193057YF045NS045）
- 朱晓丽
- 西北大学城市与环境学院, 西安 710127
- 寇志健
- 西北大学城市与环境学院, 西安 710127
- 王军强
- 1. 西北大学城市与环境学院, 西安 710127;2. 西安金博瑞生态科技有限公司, 西安 710065
- 尚小清
- 1. 西北大学城市与环境学院, 西安 710127;2. 西安金博瑞生态科技有限公司, 西安 710065
- 陈超
- 西安金博瑞生态科技有限公司, 西安 710065
- 耿盼瑶
- 西北大学城市与环境学院, 西安 710127
- 摘要：分别在300、500、700℃下限氧热解稻草、小麦和玉米秸秆制备生物炭，并以制备的生物炭为载体固定化硫酸盐还原菌（SRB），对比不同类型生物炭固定化SRB对Cd2+的吸附效果，筛选出吸附效果最佳的固定化SRB菌剂，并采用SEM、FTIR和BET对其进行表征分析；同时，研究溶液pH、吸附时间、生物炭添加量、Cd2+浓度对吸附效应的影响，并结合吸附动力学和等温吸附模型探究其对Cd2+的吸附过程及作用机理.结果表明，700℃限氧热解小麦秸秆生物炭固定化SRB菌剂（IBXM700）对Cd2+的吸附效果最佳；在pH=8、生物炭添加量为0.6 g（每50 mL溶液）、吸附时间为8 h、Cd2+初始浓度为40 mg·L-1条件下，IBXM700对Cd2+的吸附效果最佳，其吸附符合拟一级动力学模型，以离子交换和表面物理吸附为主，以化学吸附作用为辅，且符合Langmuir模型，表明是单分子层吸附；离子交换、沉淀可能是IBXM700吸附Cd2+的主要机制，阳离子-π作用为次要机制.
- Abstract：Biochar was prepared by pyrolysis of straw, wheat and corn stalks under limited oxygen at 300, 500 and 700 ℃, respectively. The prepared biochars were used as carriers for immobilization of sulfate reducing bacteria (SRB). The adsorption efficient on Cd2+ by different SRB immobilized biochar was compared, and the one with highest adsorption ability was selected for further investigation by SEM, FTIR and BET. The data showed that wheat straw biochar pyrolysed at 700 ℃ immobilizing SRB (IBXM700) showed the highest adsorption ability of Cd2+. The adsorption efficacy of IBXM700 on Cd2+ under different pH, adsorption time, biochar addition and Cd2+concentration were investigated. Moreover, the adsorption process and mechanism of IBXM700 on Cd2+ were explored on adsorption kinetics with isothermal adsorption model. The results show that the optimal adsorption conditions are pH 8, biochar addition 0.6 g per 50 mL solution, adsorption time 8 h,initial Cd2+ concentration 40 mg·L-1. The adsorption of Cd2+ by IBXM700 conforms to pseudo-first-order kinetics model. the main adsorption mechanisms include ion exchange and surface physical adsorption, and the second is chemical adsorption. Isothermal adsorption model shows that the adsorption result fits Langmuir model well. The main mechanism is monolayer adsorption, ion exchange and precipitation, and the secondary mechanism is cation-π action.
